The VAC-RE20 model is specifically designed to attach to the Electro-Voice RE20 Microphone and its 309/A shock mount (one of the radio broadcast industry standard setups.)
Simply unscrew one of the thumbscrews on either side of the shock mount, install the VAC-RE20 and put the screw back. The VAC-RE20 tracks the microphone as it is moved. Each DJ can have their own set of screens and "pop" them in for their air time, especially helpful during flu season.
Electro-Voice RE20 and 309/A are not includ